10.1 Carry-On vs Checked Decision Logic
Key Takeaways
- TSA's public packing map has four main buckets: never-fly (explosives, many flammables, and a loaded firearm, including one locked in checked baggage); checked-only (unloaded firearms, most knives, ammunition, replica firearms, bats); carry-on with 3-1-1 or quantity limits; and items allowed in both bags that may still need extra screening (food, powders, clutter).
- The final decision rests with the TSA officer on whether an item is allowed through the checkpoint; even a generally permitted item may get additional screening or be refused if it alarms, appears tampered with, or poses other security concerns (TSA What Can I Bring).
- Ordinary checked bags may use TSA-recognized locks (Travel Sentry or Safe Skies branding) so officers can inspect without cutting; a firearm case may use any brand or type of lock, including TSA-recognized, and the passenger retains the key unless TSA personnel request it (TSA Security Screening; Transporting Firearms and Ammunition).
- If TSA physically inspects a checked bag, officers place a notice of baggage inspection inside the bag; most of the about 1.3 million checked bags screened daily do not need a physical search (TSA Security Screening).
- Officers may ask a traveler to power up an electronic device, including a cell phone; powerless devices will not be permitted onboard; TSA does not read or copy information from the device (TSA What Can I Bring).
10.1 Carry-On vs Checked Decision Logic
Quick answer: Ask four public questions in order. (1) Never-fly: explosives, many flammables (gasoline, butane, gunpowder, flares, flare guns, alcoholic beverages over 70% alcohol), and a loaded firearm — including a loaded gun locked in checked baggage so the passenger cannot reach it. (2) Checked only: unloaded firearms, most knives, ammunition, replica firearms (including toy replicas), and sports equipment that can be used as a bludgeon such as bats. (3) Carry-on with quantity rules: liquids, aerosols, gels, creams, and pastes in travel-sized containers of 3.4 ounces (100 milliliters) or less, in one quart-sized bag per passenger; a snow globe must be about tennis-ball size and fit, including the base, in that bag. (4) Both bags are generally allowed, but food, powders, and clutter may need extra screening. Spare lithium batteries are a cabin-only special case from Chapter 9. The final decision rests with the TSA officer. Officers may ask you to power up a device; powerless devices will not be permitted onboard.
This section trains public packing logic for the TSO Assessment Battery (TAB) and for the checkpoint. It is not Sensitive Security Information (SSI). It does not replace What Can I Bring, Security Screening, or FAA PackSafe. The live lists are item-by-item. The tree below is how you route an item before you look it up.
TSA screens about 3.3 million carry-on bags and about 1.3 million checked bags a day for explosives and other dangerous items. How a traveler packs is not a courtesy. A jam-packed, cluttered, overstuffed bag takes time to resolve. Even if an item is generally permitted, it may get additional screening or be refused if it triggers an alarm, appears to have been tampered with, or poses other security concerns. Civil penalties exist for prohibited items; read the live Civil Enforcement table rather than inventing a fine.
The four-bucket tree
Work top-down. Do not start with "can I carry it on?" if the item is a never-fly hazard.
| Bucket | Public test | Carry-on | Checked | Examples on TSA.gov |
|---|---|---|---|---|
| 1. Never-fly | Explosive, many flammables, or a loaded firearm | No | No | Dynamite, blasting caps, gunpowder, flares, flare guns, butane, bear spray, alcoholic beverages over 140 proof, a firearm with a live round in the chamber, cylinder, or inserted magazine |
| 2. Checked only | Cabin-prohibited weapon, sharp, replica, or bludgeon that the hold still allows | No | Yes (often special instructions) | Unloaded firearms, ammunition, firearm parts, realistic replica firearms, most knives, baseball bats |
| 3. Carry-on with 3-1-1 / quantity | Liquid, gel, aerosol, cream, paste, or a liquid-filled souvenir that must meet travel-size limits | Yes, if it meets the limit | Yes (full-size) | 3.4 oz / 100 mL toiletries in one quart bag; snow globes that fit, including the base, in that bag |
| 4. Both OK, extra screening possible | Generally permitted, but dense, organic, powdery, or cluttered | Yes (officer may separate) | Yes (often recommended) | Solid food, canned foods, powders, hair dryers, organized clothing |
A fifth public exception sits beside the tree, not inside bucket 3: spare (uninstalled) lithium batteries and power banks are carry-on only (Chapter 9). Do not check them "to be safe." The hold is the wrong place for a spare cell.
Bucket 1 — never-fly, including an inaccessible loaded firearm
Flammables and the explosives listings are No / No for the items that actually detonate or fuel a fire: blasting caps, dynamite, gunpowder, consumer and professional fireworks, flares, flare guns, butane, bear spray, and alcoholic beverages with more than 70% alcohol (over 140 proof). Those objects do not become legal because they are locked, declared, or placed in the belly. Checking them does not hide them from the rule.
A loaded firearm is in the same bucket. TSA permits unloaded firearms in a locked hard-sided container as checked baggage only. A gun with a live round in the chamber, cylinder, or an inserted magazine is not "packed." Locking that loaded gun in a hard-sided case so the passenger cannot reach it in flight does not make it a legal checked item. Inaccessible is not unloaded. Section 10.2 covers declaration, state-law overlay, and ammunition packaging. This section's job is the routing rule: loaded = do not fly.
Bucket 2 — checked only
Once the item is not a never-fly hazard, ask whether the cabin is closed. TSA's live pages are blunt:
- Firearms — carry-on No; checked Yes with special instructions (unloaded, locked hard-sided container, declare to the airline).
- Ammunition — carry-on No; checked Yes with special instructions.
- Most knives — carry-on No; checked Yes, sheathed or securely wrapped. Exceptions are rounded-blade or blunt-edge knives without serration (butter knives) and plastic cutlery.
- Replica firearms, including firearm replicas that are toys — checked baggage only on the Transporting Firearms page; Realistic Replicas of Firearms is carry-on No / checked Yes.
- Baseball bats and other sports equipment that can be used as a bludgeon (bats and clubs) — carry-on No; checked Yes.
A traveler who says "it will fit in the overhead bin" has not changed a checked-only listing. Size is an airline question. Cabin prohibition is a TSA listing.
Bucket 3 — carry-on with 3-1-1 and quantity rules
The liquids rule is still the cabin limit for liquids, aerosols, gels, creams, and pastes: 3.4 ounces (100 milliliters) or less per container, in one quart-sized bag, one bag per passenger. Larger containers belong in checked baggage. Any LAG that alarms needs additional screening. Chapter 8 covers medical, infant, and duty-free exceptions. This chapter only needs the routing: if it is a liquid over travel size and no published exemption applies, check it.
Snow globes are the souvenir that travelers treat as "not a liquid." They are. A globe that appears to contain less than 3.4 ounces of liquid (about tennis-ball size) may go in carry-on only if the entire snow globe, including the base, fits in the one quart-sized bag. Larger globes go in checked baggage.
Bucket 4 — both allowed, extra screening likely
Security Screening says that in most cases fruit, health bars, and sandwiches can stay in the carry-on, and that officers may instruct travelers to separate foods, powders, and any materials that clutter bags and obstruct clear images. Canned foods are carry-on Yes (special instructions) / checked Yes. They are not on the prohibited list, but because of how they appear on the X-ray, security concerns, or 3-1-1, they may need additional screening that can still refuse the item. TSA suggests packing cans in checked bags, shipping them, or leaving them home.
For last-point-of-departure flights into the United States, TSA encourages placing powder-like substances over 12 ounces / 350 mL in checked bags; unresolved powders can be prohibited from the cabin. That is a published international-screening note, not a claim that every domestic powder is banned.
Locks, inspection notices, and powerless electronics
Ordinary checked bags. TSA has master keys under agreements with Safe Skies Luggage Locks and Travel Sentry so certain branded locks may not have to be cut for inspection. Packaging should indicate that TSA officers can open the lock. TSA has no position on those products as a security measure and will still remove them if necessary during inspection. Teach travelers that a TSA-recognized lock is a convenience for inspection, not a guarantee the bag will not be opened.
Firearm cases are a different lock rule. Any brand or type of lock, including TSA-recognized locks, may secure a firearm case. Only the passenger should retain the key or combination unless TSA personnel request the key to open the firearm container. Do not tape the key to the case. Do not hand it to a companion as a default. Section 10.2 returns to that rule in the Prepare / Pack / Declare sequence.
Inspection notices. The majority of checked bags are screened without a physical bag search. If TSA does physically inspect the property, officers place a notice of baggage inspection inside the bag. That slip means an officer opened the bag. Claims for property lost or damaged during screening go to TSA; damage during airline transport goes to the airline.
Electronics. Officers may ask you to power up a device, including a cell phone. Powerless devices will not be permitted onboard. TSA does not read or copy information from the device. An empty-looking laptop that will not turn on is not cleared because the image looks like a laptop.
Realistic scenario
A family arrives with a carry-on that holds a tennis-ball snow globe that does not fit in the quart bag, a can of soup, a hair dryer, a folding knife "for snacks," and a laptop that will not power on. The snow globe is a liquid over the published carry-on fit; it belongs in checked baggage. The soup can is both-bags with special instructions — extra screening is likely, and TSA already suggests checking it. The hair dryer is Yes / Yes and is not on the remove-electronics list, but it is clutter if it sits on a tablet. The knife is checked only. The dead laptop is a powerless device and will not be permitted onboard. A second traveler's unloaded hunting rifle in a locked hard-sided case, declared at the ticket counter, is bucket 2 — not the checkpoint. A third traveler's pistol with a round in the chamber, even locked in that same style of case, is bucket 1: never-fly. The final decision rests with the TSA officer.
Which statement matches TSA's published carry-on versus checked decision logic?
How do TSA's published lock rules differ for an ordinary checked suitcase and a firearm case?
A traveler's carry-on holds canned soup, loose powder, and a laptop that will not power on. The same traveler's checked suitcase was physically opened during screening. Which published rules apply?